Fix impossibility to make @Optional field in a class hierarchy on JS

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/JsCodegenUtil.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.js.translate.utils.JsAstUtils
 import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtPureClassOrObject
 import org.jetbrains.kotlin.resolve.descriptorUtil.classId
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.typeUtil.isTypeParameter
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.bodyPropertiesDescriptorsMap
@@ -172,7 +173,13 @@ internal fun SerializerJsTranslator.serializerInstance(
     }
 }
 
-fun TranslationContext.buildInitializersRemapping(forClass: KtPureClassOrObject): Map<PropertyDescriptor, KtExpression?> = forClass.run {
+fun TranslationContext.buildInitializersRemapping(
-    (bodyPropertiesDescriptorsMap(bindingContext()).mapValues { it.value.delegateExpressionOrInitializer } +
+    forClass: KtPureClassOrObject,
-            primaryPropertiesDescriptorsMap(bindingContext()).mapValues { it.value.defaultValue })
+    superClass: ClassDescriptor?
+): Map<PropertyDescriptor, KtExpression?> {
+    val myMap = (forClass.bodyPropertiesDescriptorsMap(bindingContext()).mapValues { it.value.delegateExpressionOrInitializer } +
+            forClass.primaryPropertiesDescriptorsMap(bindingContext()).mapValues { it.value.defaultValue })
+    val parentPsi = superClass?.takeIf { it.isInternalSerializable }?.findPsi() as? KtPureClassOrObject ?: return myMap
+    val parentMap = buildInitializersRemapping(parentPsi, superClass.getSuperClassNotAny())
+    return myMap + parentMap
 }

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializableJsTranslator.kt

@@ -32,6 +32,7 @@ import org.jetbrains.kotlin.js.translate.utils.JsAstUtils
 import org.jetbrains.kotlin.js.translate.utils.TranslationUtils
 import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtPureClassOrObject
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializableCodegen
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.anonymousInitializers
@@ -44,7 +45,7 @@ class SerializableJsTranslator(
     val context: TranslationContext
 ) : SerializableCodegen(descriptor, context.bindingContext()) {
 
-    private val initMap: Map<PropertyDescriptor, KtExpression?> = context.buildInitializersRemapping(declaration)
+    private val initMap: Map<PropertyDescriptor, KtExpression?> = context.buildInitializersRemapping(declaration, descriptor.getSuperClassNotAny())
 
     override fun generateInternalConstructor(constructorDescriptor: ClassConstructorDescriptor) {
 

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/js/SerializerJsTranslator.kt

@@ -33,6 +33,7 @@ import org.jetbrains.kotlin.js.translate.utils.JsDescriptorUtils
 import org.jetbrains.kotlin.js.translate.utils.TranslationUtils
 import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtPureClassOrObject
+import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.types.typeUtil.builtIns
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializerCodegen
 import org.jetbrains.kotlinx.serialization.compiler.backend.common.getSerialTypeInfo
@@ -131,26 +132,29 @@ class SerializerJsTranslator(descriptor: ClassDescriptor,
     }
 
     private fun TranslationContext.referenceMethod(clazz: ClassDescriptor, name: String) =
-        clazz.getFuncDesc(name).single().let { getNameForDescriptor(it) }
+        getNameForDescriptor(clazz.getFuncDesc(name).single())
 
     override fun generateSave(function: FunctionDescriptor) = generateFunction(function) { jsFun, ctx ->
         val encoderClass = serializerDescriptor.getClassFromSerializationPackage(SerialEntityNames.ENCODER_CLASS)
         val kOutputClass = serializerDescriptor.getClassFromSerializationPackage(SerialEntityNames.STRUCTURE_ENCODER_CLASS)
         val wBeginFunc = ctx.getNameForDescriptor(
-                encoderClass.getFuncDesc(CallingConventions.begin).single { it.valueParameters.size == 2 })
+            encoderClass.getFuncDesc(CallingConventions.begin).single { it.valueParameters.size == 2 })
         val serialClassDescRef = JsNameRef(context.getNameForDescriptor(anySerialDescProperty!!), JsThisRef())
-        val initializersMap: Map<PropertyDescriptor, KtExpression?> = context.buildInitializersRemapping(
+
-            (serializableDescriptor.findPsi() as? KtPureClassOrObject)
+        val serializableSource = ((serializableDescriptor.findPsi() as? KtPureClassOrObject)
-                ?: throw AssertionError("Serializable descriptor $serializableDescriptor must have source file to build initializers map")
+            ?: throw AssertionError("Serializable descriptor $serializableDescriptor must have source file to build initializers map"))
-        )
+        val initializersMap: Map<PropertyDescriptor, KtExpression?> =
+            context.buildInitializersRemapping(serializableSource, serializableDescriptor.getSuperClassNotAny())
 
         // output.writeBegin(desc, [])
         val typeParams = serializableDescriptor.declaredTypeParameters.mapIndexed { idx, _ ->
             JsNameRef(context.scope().declareName("$typeArgPrefix$idx"), JsThisRef())
         }
-        val call = JsInvocation(JsNameRef(wBeginFunc, JsNameRef(jsFun.parameters[0].name)),
+        val call = JsInvocation(
-                                serialClassDescRef,
+            JsNameRef(wBeginFunc, JsNameRef(jsFun.parameters[0].name)),
-                                JsArrayLiteral(typeParams))
+            serialClassDescRef,
+            JsArrayLiteral(typeParams)
+        )
         val objRef = JsNameRef(jsFun.parameters[1].name)
         // output = output.writeBegin...
         val localOutputName = jsFun.scope.declareFreshName("output")